Emergency alert systems (EAS) are used to communicate vital information to the public during emergency situations. This information is generally conveyed to the public via televisions or public addressing systems.
The EAS in the United States is composed of analog radio broadcast stations including AM, FM, and Low-power FM (LPFM) stations; digital audio broadcasting (DAB) stations, including digital AM, FM, and Low-power FM stations; analog television broadcast stations including Class A television (CA) and Low-power TV (LPTV) stations; digital television (DTV) broadcast stations, including digital CA and digital LPTV stations; analog cable systems; digital cable systems which are the portion of a cable system that delivers channels in digital format to subscribers at the input of a Unidirectional Digital Cable Product or other navigation device; wireline video systems; wireless cable systems which may consist of Broadband Radio Service (BRS), or Educational Broadband Service (EBS) stations; DBS services, including certain Ku-band Fixed-Satellite Service Direct to Home providers; SDARS; participating broadcast networks, cable networks and program suppliers; and other entities and industries operating on an organized basis during emergencies at the National, State and local levels. These entities are referred to collectively as the Emergency Alert System (the EAS). At a minimum, the participants making up the EAS must use a common EAS protocol to send and receive emergency alerts.
The common EAS protocol includes plans to use the EAS header codes and messages that will be transmitted by key EAS sources (NP, LP, SP and SR). State and local plans contain unique methods of EAS message distribution such as the use of the Radio Broadcast Data System (RBDS). The EAS uses a four part message for an emergency activation of the EAS. The four parts are: Preamble and EAS Header Codes; audio Attention Signal; message; and, Preamble and EAS End Of Message (EOM) Codes. The message may be audio, video or text. Characters are ASCII seven bit characters as defined in ANSI X3.4-1977 ending with an eighth null bit (either 0 or 1) to constitute a full eight-bit byte.
The EAS protocol, including any codes, is dictated by the government. The EAS protocol and message format are specified in the following representation.    [PREAMBLE]ZCZC-ORG-EEE-PSSCCC+TTTT-JJJHHMM-LLLLLLLL-(one second pause)    [PREAMBLE]ZCZC-ORG-EEE-PSSCCC+TTTT-JJJHHMM-LLLLLLLL-(one second pause)    [PREAMBLE]ZCZC-ORG-EEE-PSSCCC+TTTT-JJJHH MM-LLLLLLLL-(at least a one second pause)    (transmission of 8 to 25 seconds of Attention Signal)    (transmission of audio, video or text messages)    (at least a one second pause)    [PREAMBLE]NNNN (one second pause)    [PREAMBLE]NNNN (one second pause)    [PREAMBLE]NNNN (at least one second pause)    [PREAMBLE] This is a consecutive string of bits (sixteen bytes of AB hexadecimal [8 bit byte 10101011]) sent to clear the system, set AGC and set asynchronous decoder clocking cycles. The preamble must be transmitted before each header and End Of Message code.    ZCZC—This is the identifier, sent as ASCII characters ZCZC to indicate the start of ASCII code.    ORG—This is the Originator code and indicates who originally initiated the activation of the EAS. These codes are specified by law.    EEE—This is the Event code and indicates the nature of the EAS activation. The Event codes are specified by law. The Event codes must be compatible with the codes used by the NWS Weather Radio Specific Area Message Encoder (WRSAME).    PSSCCC—This is the Location code and indicates the geographic area affected by the EAS alert. There may be 31 Location codes in an EAS alert. The Location code uses the Federal Information Processing Standard (FIPS) numbers as described by the U.S. Department of Commerce in National Institute of Standards and Technology publication FIPS PUB 6-4. Each state is assigned an SS number as specified by law. Each county and some cities are assigned a CCC number. A CCC number of 000 refers to an entire State or Territory. P defines county subdivisions as follows: 0=all or an unspecified portion of a county, 1=Northwest, 2=North, 3=Northeast, 4=West, 5=Central, 6=East, 7=Southwest, 8=South, 9=Southeast. Other numbers may be designated later for special applications. The use of county subdivisions will probably be rare and generally for oddly shaped or unusually large counties. Any subdivisions must be defined and agreed to by the local officials prior to use.    +TTTT—This indicates the valid time period of a message in 15 minute segments up to one hour and then in 30 minute segments beyond one hour; i.e., +0015, +0030, +0045, +0100, +0430 and +0600.    JJJHHMM—This is the day in Julian Calendar days (JJJ) of the year and the time in hours and minutes (HHMM) when the message was initially released by the originator using 24 hour Universal Coordinated Time (UTC).    LLLLLLLL—This is the identification of the EAS Participant, NWS office, etc., transmitting or retransmitting the message. These codes will be automatically affixed to all outgoing messages by the EAS encoder.    NNNN—This is the End of Message (EOM) code sent as a string of four ASCII N characters.
Enhancements to the Emergency Alert System have been proposed. Specifically, the Commercial Mobile Service Alert Initiative has been created to allow wireless cellular carriers to transmit emergency alert messages to cell phones and other devices having text message capabilities; see http://www.fcc.gov/pshs/cmsaac/docs/pdf/Charter.pdf. Yet these proposals fail to dynamically supply local contextually important information to particular recipients of the message.
As can be appreciated from the discussion above, conventional emergency alert systems may generally have sent notification messages to recipients over a relatively wide geographic area to alert the recipients of an emergency situation, but have failed to provide local contextually important information to particular recipients of the messages.
Therefore a need exists to overcome the problems with the prior art as discussed above.